Sorry, Flora; Uninvited Writer is correct about being able to change/add category and subcategory (Thank goodness!). Just click the edit your hub option and then right at the veryvery top of the page, you'll see the current category with another option to edit. I've have to do it couple times when I didn't know what subcategories to put a hub under when I first published it and then had to go back and change it when I saw someone else's hub on the same topic.

However, you're right about not being able to change the URL -- which would be REALLY nice, especially if you make changes to your title.

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